Advances in electronics and technology have made it possible to incorporate a variety of advanced features on automotive vehicles. Various sensing technologies have been developed for detecting objects in a vicinity or pathway of a vehicle. Such systems are useful for parking assist and cruise control adjustment features, for example.
More recently, automated vehicle features have become possible to allow for autonomous or semi-autonomous vehicle control. For example, cruise control systems may incorporate LIDAR (light detection and ranging) for detecting an object or another vehicle in the pathway of the vehicle. Depending on the approach speed, the cruise control setting may be automatically adjusted to reduce the speed of the vehicle based on detecting another vehicle in the pathway of the vehicle.
There are different types of LIDAR systems. Flash LIDAR relies upon a single laser source to illuminate an area of interest. Reflected light from an object is detected by an avalanche photodiode array. While such systems provide useful information, the avalanche photodiode array introduces additional cost because it is a relatively expensive component. Additionally, the laser source for such systems has to be relatively high power to achieve sufficiently uniform illumination of the area of interest. Scanning LIDAR systems utilize different components compared to flash LIDAR. One challenge associated with previously proposed scanning LIDAR systems is that additional space is required for the scanning components, such as a mirror array, and there is limited packaging space available on vehicles. Optical phase array LIDAR systems utilize beam multiplexing that tends to introduce relatively significant power loss.
There is a need for improvements in components for systems, such as LIDAR systems, that are lower-cost, easier to fit within small packaging constraints, and utilize power efficiently. For example, micro-electro-mechanical (MEMs) mirror arrays are typically open loop devices that do not have accurate position feedback information. Without such information precise control over a beam direction can be difficult and the range of the scanning angle is limited. Previous attempts to include position feedback capabilities have introduced complexities, additional components and increased cost, all of which are undesirable when tight packaging constraints and cost are concerns.